Jativa Vega, Sofia Alejandra;
(2020)
A second look at memory: Different Approaches to Understanding Diversity in Memory and Cognition.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Memory lies at the heart of human cognitive abilities. Therefore, understanding it from neural, psychological and computational viewpoints is of key importance for computational neuroscience, psychology and beyond. In this thesis, I explore two prominent, but different, memory systems: episodic memory and working memory. First, I propose a modification to a recent reinforcement learning algorithm for decision making in which single memories of events, i.e., episodic memories, are integrated to compute the long run value of actions. I argue that these memories are recalled and that their contributions are weighted based on context. Further, I propose that predictions made by this algorithm are combined with those that come from a standard, model-free, reinforcement learning algorithm. I suggest that humans can flexibly choose between these two sources of information to make decisions and guide actions. I show that the resulting combined model best fits data on human choices, outperforming previously proposed models. To complement these algorithmic and psychological suggestions, I present a generative model of the world according to which this sort of episodic recall is an appropriate method for making inferences and predictions of future rewards. Contrary to other suggestions for reward-based learning, this generative model can model events that not only drift continuously in time, but can also suddenly change to new or repeated events. Turning to working memory, I use information theoretic analyses to show that dynamic synapses, whose strengths adjust with usage, can increase its capacity. I argue that these components should be included in the study of working memory. The thesis ends with an explanation of the connections between these memory systems.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | A second look at memory: Different Approaches to Understanding Diversity in Memory and Cognition |
| Event: | UCL |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Gatsby Computational Neurosci Unit |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10097002 |
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